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+Network Working Group D. Spinellis
+Request for Comments: 1947 SENA S.A.
+Category: Informational May 1996
+
+
+ Greek Character Encoding for Electronic Mail Messages
+
+Status of This Memo
+
+ This memo provides information for the Internet community. This memo
+ does not specify an Internet standard of any kind. Distribution of
+ this memo is unlimited.
+
+Overview and Rational
+
+ This document describes a standard encoding for electronic mail
+ [RFC822] containing Greek text and provides implementation guide-
+ lines. The standard is based on MIME [RFC1521] and the ISO 8859-7
+ character encoding. Although the implementation of this standard is
+ straightforward several non-standard but "functional" - though
+ unlikely to inter-operate - alternatives are in common use. For this
+ reason we highlight common implementation and mail user agent setup
+ errors.
+
+ Description
+
+ In order to transfer Greek text via electronic mail the text is first
+ translated into the ISO 8859-7 character set, and then encoded using
+ either the Base64 (preferable for text that is mainly Greek) or the
+ Quoted-Printable (justifiable in cases where some Greek words appear
+ inside predominately Latin text) method, as defined in MIME.
+
+ The following table provides most common Greek encodings (see also
+ [RFC1345]):
+
+ 0646 37 M7 51 MC 23 69 LG L1 G7 GO GC 28 97 Description
+ ---- -- -- -- -- -- -- -- -- -- -- -- -- -- -----------
+ 0386 ea a2 86 cd 71 86 b6 Capital alpha with acute
+ 0388 eb b8 8d ce 72 8d b8 Capital epsilon with
+ acute
+ 0389 ec b9 8f d7 73 8f b9 Capital eta with acute
+ 038a ed ba 90 d8 75 90 ba Capital iota with acute
+ 038c ee bc 92 d9 76 92 bc Capital omicron with
+ acute
+ 038e ef be 95 da 77 95 be Capital upsilon with
+ acute
+ 038f f0 bf 98 df 78 98 bf Capital omega with acute
+ 0390 c0 a1 fd a1 c0 Small iota with acute and
+
+
+
+Spinellis Informational [Page 1]
+
+RFC 1947 Greek Encoding for E-mail Messages May 1996
+
+
+ diaeresis
+ 0391 80 c1 a4 b0 41 a4 61 41 61 41 41 c1 Capital alpha
+ 0392 81 c2 a5 b5 42 a5 62 42 62 42 42 c2 Capital beta
+ 0393 82 c3 a6 a1 43 a6 67 23 43 67 43 44 c3 Capital gamma
+ 0394 83 c4 a7 a2 44 a7 64 40 44 64 44 45 c4 Capital delta
+ 0395 84 c5 a8 b6 45 a8 65 45 65 45 46 c5 Capital epsilon
+ 0396 85 c6 a9 b7 46 a9 7a 46 7a 46 49 c6 Capital zeta
+ 0397 86 c7 aa b8 47 aa 68 47 68 47 4a c7 Capital eta
+ 0398 87 c8 ac a3 48 ac 75 5c 48 75 48 4b c8 Capital theta
+ 0399 88 c9 ad b9 49 ad 69 49 69 49 4c c9 Capital iota
+ 039a 89 ca b5 ba 51 b5 6b 4b 6b 4a 4d ca Capital kappa
+ 039b 8a cb b6 a4 52 b6 6c 5e 4c 6c 4b 4e cb Capital lamda
+ 039c 8b cc b8 bb 53 b7 6d 4d 6d 4c 4f cc Capital mu
+ 039d 8c cd b7 c1 54 b8 6e 4e 6e 4d 50 cd Capital nu
+ 039e 8d ce bd a5 55 bd 6a 21 4f 6a 4e 51 ce Capital xi
+ 039f 8e cf be c3 56 be 6f 50 6f 4f 52 cf Capital omicron
+ 03a0 8f d0 c6 a6 57 c6 70 3f 51 70 50 53 d0 Capital pi
+ 03a1 90 d1 c7 c4 58 c7 72 52 72 51 55 d1 Capital rho
+ 03a3 91 d3 cf aa 59 cf 73 5f 53 73 53 56 d3 Capital sigma
+ 03a4 92 d4 d0 c6 62 d0 74 54 74 54 58 d4 Capital tau
+ 03a5 93 d5 d1 cb 63 d1 79 55 79 55 59 d5 Capital upsilon
+ 03a6 94 d6 d2 bc 64 d2 66 5d 56 66 56 5a d6 Capital phi
+ 03a7 95 d7 d3 cc 65 d3 78 58 78 57 5b d7 Capital chi
+ 03a8 96 d8 d4 be 66 d4 63 3a 59 63 58 5c d8 Capital psi
+ 03a9 97 d9 d5 bf 67 d5 76 5b 5a 76 59 5d d9 Capital omega
+ 03aa da ab 91 da Capital iota with
+ diaeresis
+ 03ab db bd 96 db Capital upsilon with
+ diaeresis
+ 03ac e1 dc 9b c0 b1 9b dc Small alpha with acute
+ 03ad e2 dd 9d db b2 9d dd Small epsilon with acute
+ 03ae e3 de 9e dc b3 9e de Small eta with acute
+ 03af e5 df 9f dd b5 9f df Small iota with acute
+ 03b0 e0 fc fe fc e0 Small upsilon with acute
+ and diaeresis
+ 03b1 98 e1 d6 e1 8a d6 61 41 61 61 e1 Small alpha
+ 03b2 99 e2 d7 e2 8b d7 62 42 62 62 e2 Small beta
+ 03b3 9a e3 d8 e7 8c d8 63 47 63 64 e3 Small gamma
+ 03b4 9b e4 dd e4 8d dd 64 44 64 65 e4 Small delta
+ 03b5 9c e5 de e5 8e de 65 45 65 66 e5 Small epsilon
+ 03b6 9d e6 e0 fa 8f e0 66 5a 66 69 e6 Small zeta
+ 03b7 9e e7 e1 e8 9a e1 67 48 67 6a e7 Small eta
+ 03b8 9f e8 e2 f5 9b e2 68 55 68 6b e8 Small theta
+ 03b9 a0 e9 e3 e9 9c e3 69 49 69 6c e9 Small iota
+ 03ba a1 ea e4 eb 9d e4 6b 4b 6a 6d ea Small kappa
+ 03bb a2 eb e5 ec 9e e5 6c 4c 6b 6e eb Small lamda
+ 03bc a3 ec e6 ed 9f e6 6d 4d 6c 6f ec Small mu
+ 03bd a4 ed e7 ee aa e7 6e 4e 6d 70 ed Small nu
+
+
+
+Spinellis Informational [Page 2]
+
+RFC 1947 Greek Encoding for E-mail Messages May 1996
+
+
+ 03be a5 ee e8 ea ab e8 6f 4a 6e 71 ee Small xi
+ 03bf a6 ef e9 ef ac e9 70 4f 6f 72 ef Small omicron
+ 03c0 a7 f0 ea f0 ad ea 71 50 70 73 f0 Small pi
+ 03c1 a8 f1 eb f2 ae eb 72 52 71 75 f1 Small rho
+ 03c2 aa f2 ed f7 af ed 77 57 72 77 f2 Small final sigma
+ 03c3 a9 f3 ec f3 ba ec 73 53 73 76 f3 Small sigma
+ 03c4 ab f4 ee f4 bb ee 74 54 74 78 f4 Small tau
+ 03c5 ac f5 f2 f9 bc f2 75 59 75 79 f5 Small upsilon
+ 03c6 ad f6 f3 e6 bd f3 76 46 76 7a f6 Small phi
+ 03c7 ae f7 f4 f8 be f4 78 58 77 7b f7 Small chi
+ 03c8 af f8 f6 e3 bf f6 79 43 78 7c f8 Small psi
+ 03c9 e0 f9 fa f6 db fa 7a 56 79 7d f9 Small omega
+ 03ca e4 fa a0 fb b4 a0 fa Small iota with diaeresis
+ 03cb e8 fb fb fc b8 fb fb Small upsilon with
+ diaeresis
+ 03cc e6 fc a2 de b6 a2 fc Small omicron with acute
+ 03cd e7 fd a3 e0 b7 a3 fd Small upsilon with acute
+ 03ce e9 fe fd f1 b9 fd fe Small omega with acute
+
+ Note: All values are in hexadecimal.
+
+ The column headers refer to the following character sets:
+
+0646 The ISO 2DIS 10646 code.
+
+37 PC code page 737 also known as 437G. Note that some implementa-
+ tions of this code page do not include capital letters with acute.
+
+M7 Character set 8859-7 as implemented in Microsoft Windows 3.1,
+ Microsoft Windows 3.11, and Microsoft Windows 95.
+
+51 IBM code page 851.
+
+MC The Greek code page implemented on the Apple Macintosh computers.
+
+23 IBM code page 423 (EBCDIC-CP-GR).
+
+69 IBM code page 869.
+
+LG Latin Greek (iso-ir-19).
+
+L1 Latin Greek 1 (iso-ir-27). This page only contains the Greek cap-
+ ital letters whose glyphs do not exist in the Latin alphabet. The
+ other capital letters are rendered using the equivalent Latin let-
+ ter (e.g. "Greek capital letter alpha" is rendered as "Latin capi-
+ tal letter A"). When mapping "Latin Greek 1" text to ISO 8859-7
+ the Latin capital letters should only be transcribed to the
+ equivalent Greek ones if a suitable heuristic determines that the
+
+
+
+Spinellis Informational [Page 3]
+
+RFC 1947 Greek Encoding for E-mail Messages May 1996
+
+
+ specific Latin letters are used to represent Greek glyphs.
+
+G7 7 bit Greek (iso-ir-88).
+
+GO Old 7 bit Greek (iso-ir-18).
+
+GC Greek CCITT (iso-ir-150).
+
+28 Character set ISO 5428:1980 (iso-ir-55).
+
+97 The target character set ISO 8859-7:1987 (ELOT-928) (iso-ir-126).
+
+MIME Headers
+
+ A mail message that contains Greek text must contain at least the
+ following MIME headers:
+
+ MIME-Version: 1.0
+ Content-type: text/plain; charset=ISO-8859-7
+ Content-transfer-encoding: BASE64 | Quoted-Printable
+
+ In the future, when all email systems implement fully transparent
+ 8-bit e-mail as defined in RFC 1425 and RFC 1426 the message body
+ encoding phase described in this standard will be no longer
+ needed. In this case the requisite MIME headers are modified as
+ follows:
+ MIME-Version: 1.0
+ Content-type: text/plain; charset=ISO-8859-7
+ Content-transfer-encoding: 8BIT
+ Even when RFC 1425 is used, Q or B encoding will continue to apply
+ to message headers as detailed in the following section.
+
+ Optional
+
+ It is recommended, although not required, to support Greek encod-
+ ing in mail headers as specified in RFC 1522. Specifically, the
+ B-encoding format is to be the default method used for encoding
+ Greek text in RFC-822 mail headers, and the Q-encoding format the
+ method to use for the exceptional case of encoding a single Greek
+ word or letter in an otherwise Latin-character-based header.
+
+
+
+
+
+
+
+
+
+
+
+Spinellis Informational [Page 4]
+
+RFC 1947 Greek Encoding for E-mail Messages May 1996
+
+
+Example
+
+ Below is a short example of Quoted-Printable encoded Greek
+ email:
+
+ Date: Wed, 31 Jan 96 20:15:03 EET
+ From: Diomidis Spinellis <dds@senanet.com>
+ Subject: Sample Greek mail
+ To: Achilleas Voliotis <achilles@theseas.ntua.gr>
+ MIME-Version: 1.0
+ Content-ID: <Wed_Feb_14_18_49_50_EET_1996_0@senanet>
+ Content-Type: Text/plain; charset=ISO-8859-7
+ Content-Transfer-Encoding: Base64
+
+yuHr5+zd8eEsCgrU7yDl6+vn7enq/CDh6/bc4uf07yDh8O/05evl3/Th6SDh8PwgMjYg4/Hc
+7Ozh9OEuCg==
+
+Discussion
+
+ It is possible [RFC1428] (and unfortunately common practice) to
+ set up an arrangement of mail user and transfer agents that allow
+ end users to communicate with Greek e-mail messages while
+ violating a number of standards. Such arrangements are unlikely
+ to offer wide scale interoperability.
+
+ One common error is to arrange the rendering and composition of
+ Greek messages by rigging a mail user agent hosted in an ISO
+ 8859-1 environment to use a presentation font that contains Greek
+ glyphs and a keyboard input method that generates Greek text using
+ those glyphs. The resulting messages begin with header items
+ indicating contents in the ISO 8859-1 character set and include
+ text in a totally different encoding. Unfortunately this
+ "solution" appears to "work" across similar systems and is widely
+ used.
+
+ One other error is to tag Greek text generated on Microsoft
+ Windows platforms as ISO 8859-7 without an intermediate
+ translation phase. It is important to note that the character set
+ used by the Microsoft Windows Greek implementations is NOT the
+ same as the ISO 8859-7 representation. First of all, the
+ character set used to represent Greek characters differs slightly
+ from the ISO 8859-7 encoding (this difference was instrumented in
+ order to rectify the appearance of an early version of Microsoft
+ Word for Windows in which the end-of-section symbol clashed with
+ the "Greek capital alpha with acute" glyph). In addition, a
+ number of 8-bit characters available on Greek Windows
+ implementations are not part of the ISO 8859-7 character set.
+
+
+
+
+Spinellis Informational [Page 5]
+
+RFC 1947 Greek Encoding for E-mail Messages May 1996
+
+
+ Note that the ISO 8859-7 encoding is equivalent to the Greek
+ Standards Organisation ELOT-928 encoding.
+
+References
+
+ [ISO-8859] Information Processing -- 8-bit Single-Byte Coded Graphic
+ Character Sets, Part 7: Latin/Greek alphabet, ISO 8859-7,
+ 1987.
+
+ [RFC822] Crocker, D., "Standard for the Format of ARPA Internet
+ Text Messages", STD 11, RFC 822, UDEL, August 1982.
+
+ [RFC1345] Simonsen, K., "Character Mnemonics & Character Sets" RFC
+ 1345, Rationel Almen Planlaegning, June 1992.
+
+ [RFC1425] Klensin, J., Freed N., Rose M., Stefferud E., and D.
+ Crocker, "SMTP Service Extensions", RFC 1425, United
+ Nations University, Innosoft International, Inc., Dover
+ Beach Consulting, Inc., Network Management Associates,
+ Inc., The Branch Office, February 1993.
+
+ [RFC1426] Klensin, J., Freed N., Rose M., Stefferud E., and D.
+ Crocker, "SMTP Service Extension for 8bit-MIME Transport",
+ RFC 1426, United Nations University, Innosoft
+ International, Inc., Dover Beach Consulting, Inc., Network
+ Management Associates, Inc., The Branch Office, February
+ 1993.
+
+ [RFC1428] Vaudreuil, G., "Transition of Internet Mail from
+ Just-Send-8 to 8bit-SMTP/MIME", RFC 1428, CNRI, February
+ 1993.
+
+ [RFC1521] Borenstein N., and N. Freed, "MIME (Multipurpose Internet
+ Mail Extensions) Part One: Mechanisms for Specifying and
+ Describing the Format of Internet Message Bodies",
+ Bellcore, Innosoft, September 1993.
+
+ [RFC1522] Moore K., "MIME Part Two: Message Header Extensions for
+ Non-ASCII Text", University of Tennessee, September 1993.
+
+
+
+
+
+
+
+
+
+
+
+
+Spinellis Informational [Page 6]
+
+RFC 1947 Greek Encoding for E-mail Messages May 1996
+
+
+Security Considerations
+
+ Security issues are not discussed in this memo.
+
+Author's Address
+
+ Diomidis Spinellis
+ SENA S.A.
+ Kyprou 27
+ GR-152 47 Filothei
+ GREECE
+
+ Phone: +30 (1) 6854535
+ Fax: +30 (1) 6840631
+ EMail: D.Spinellis@senanet.com
+
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+Spinellis Informational [Page 7]
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